Accumulation heavy Metals (Zn, Cu, Ni, Pb and Cd) in sediment and stone snail Tylothais savignyi in the kharg Island during summer and winter

This study was carried out to determine the level of heavy metals contamination in the sediments and stone snail Tylothais savignyi from Kharg Island and to determine the potential of the snail to serve as a biomonitoring agent. A sampling of surface sediments and snail was carried out from five different stations in September 2013 and March 2014. Samples were transferred to the laboratory and oven-dried. The samples then were acid digested and their heavy metals content was measured using GBC flame atomic absorption spectrophotometer (model Savantaa Σ, Australia). The results showed that the concentrations of copper, zinc, nickel, and lead in the sediment of Kharg Island was in the range of 26.4- 38.2, 63.9-75, 35.7-52.6, and 27.2-35.9 μg/g of dry weight, respectively, while cadmium concentrations were below the detection limit of the apparatus. The concentrations of copper, zinc, nickel, lead and cadmium in the soft tissue of the T. savignyi were 362.3-590, 127.4-183, 6.9-11.2, 24.1-43.9, and 8.4-18.2 μg/g of dry weight, respectively. Similarly, the concentrations of copper, zinc, nickel, and lead in snails shells were 31.5-49.4, 18.2-24.5, 7.1-8, and 27.4-33.9 μg/g, respectively. Similar to the sediments, cadmium concentrations were below the detection limit of AAs. The comparison of the results with previous studies and the available standards showed that heavy metal concentrations in the sediments were lower than the standard levels. Meanwhile, the concentrations of copper, nickel, lead, and cadmium in the soft tissue of the snail were appeared higher than standard levels. These results indicate that the snail has a strong capacity to accumulate heavy metals from its surrounding environment. Therefore, the snail has a significant ability to accumulate metals in its soft tissue.